Centerless grinding machine



CENTERLESS GRINDING MACHINEv Filed oct. 1e, '1967 g 4 sheets-snaai 1 401' Tae/V596.

Nov. 3, 1970 H. E. CONLEY 3,537,213

I CENTERLESS GRINDING MACHINE 'Filled oct'. 1e, 1967 4 Asheets-sheet lz lfaa.

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Nov. 3, 1970 H. E. CONLEY CENTERLESS GRINDING MACHINE 4 Sheets-Sheet 3 Filed Oct. 16. 1967 TTo/eNEs/s.

Nov. 3, ...1970

H. E. coNLEYl CENTERLESS GRINDING MACHINE .4-Sneets-Sheet 4 Filed Oct. 16, 1967 JJM rroQNEs/s.

United States Patent Otiice 3,537,213 Patented Nov. 3, 1970 3,537,213 CENTERLESS GRINDING MACHINE Hollet E. Conley, Glendale, Calif., assignor of one-half to Allan F. Ross, Van Nuys, Calif. Filed Oct. 16, 1967, Ser. No. 675,533 Int. Cl. B24b 5/18 U.S. Cl. 51-103 3 Claims ABSTRACT OF THE DISCLOSURE A regilating wheel support assembly including a main base mounted for horizontal movement relative to a fixed axis grinding *wheel and a sub-base for rotatably mounting the regulating wheel which is mounted on the main base for relative movement therewith in a plane inclined to the horizontal for adjusting the position of the regulating wheel relative to the stationary axis grinding wheel, the plane of regulating wheel movement being inclined upwardly away from a point of zero clearance between the wheels, The plane in which the regulating wheel is adjustably movable by its sub-base on the assembly main base is specifically determined so that the regulating wheel is adjustable to successively contact a plurality of different diameter workpieces to be ground between the wheels at contact points on the workpieces which are level with the workpiece centers when different diameter workpieces are successively supported on the work support means without the necessity of changing the positioningof the work support and grinding wheel relative to the machine bed.

The provision of a constant blade angle of 24 and 7 for the work rest blade portion of the workpiece support and a regulating feed angle, defined by the plane of movement of the regulating wheel sub-base on its main base, of 1840 so that a plurality of different diameter workpieces may be successively ground on said machine by adjusting the regulating -wheel position relative to the grinding wheel and work support blade, such different diameter workpieces each being maintained during grinding a distance above a horizontal plane through the grinding wheel center line equal to approximately one-third their diameters and the regulating wheel contacting such workpieces at points thereon approximately level with their centers.

BACKGROUND OF THE INVENTION The art of cylindrical grinding was greatly improved by the introduction of the centerless grinding machine some forty or more years ago wherein the workpiece to be ground is maintained against the grinding wheel surface by the combined support of a work support blade and a regulating wheel, the regulating wheel also functioning as a friction driving and braking means for rotating the work at a constant and uniform surface speed approximately equal to that of the regulating wheel. The materials used for the grinding and regulating wheels have been developed and very complex and expensive centerless grinding machines have been developed particularly for production runs of close tolerance parts. However, these prior centerless grinding machines have had the distinct disadvantage of requiring considerable setup time between production runs in order to adjust the relative positioning of the grinding wheel, work support and regulating wheels relative to the machine base.

In the typical small job shop operation, it is difficult to plan long production runs of any parts since orders are generally received in small lots of varying types and dimensions. The job shop operator can neither afford the prior expensive and sophisticated centerless grinding machines generally available nor can he afford the time to complete complicated setup operations between each short run of different diameter workpieces. This problem in the job shop operation is generally recognized in the trade with present day centerless grinding machine manufacturers suggesting that job shop operators attempt to try to group lots of parts whose diameters are not too different so that the changes in setup will come in as small steps as possible. Such suggestions do not solve the problem for the job shop operator but merely complicate his efforts to produce small lots of articles on a day to day delivery basis.

It is therefore the primary object of the present invention to provide an improvement in centerless grinding machines employing a grinding wheel, a work support plate and a regulating wheel which is easily adjustable for receiving and grinding different diameter -workpieces in succession with a minimum of setup time between the grinding of parts of different diameters.

It is another object of the present invention to disclose and provide an improvement in centerless grinding machines which is particularly adapted for successively grinding a plurality of different diameter workpieces with a minimum of setup time and which is of a relatively simple construction allowing manufacture and sale thereof at prices which will allow the typical job shop operator to be able to afford the initial investment for and continued profitable operation of a centerless grinding machine.

It is also an object of the present invention to disclose and provide an improvement in centerless grinding machines as in the foregoing objects wherein the grinding wheel is mounted for rotation about a fixed axis relative to the machine bed, where a work support having a constant blade angle is employed and where the regulating wheel is mounted on a regulating wheel support assembly providing horizontal movement of the regulating wheel relative to the machine bed and fixed axis grinding wheel in an easy and simple manner for setup operations and is thereafter easily and accurately readily adjustable in a predetermined plane which is inclined to a point of zero clearance between the wheels so that a plurality of different diameter workpieces may be ground between the wheels by merely adjusting the position of the regulating wheel in its inclined plane of movement without the necessity of changing the grinding wheel mounting position nor the work support blade angle.

It is also an object of the present invention to disclose and provide an improvement in centerless grinding machines as in the foregoing objects wherein the provision of a constant blade angle for the work support together with a predetermined plane of movement for adjustment of the regulating wheel relative to the blade and fixed axis grinding wheel maintains each of a plurality of different diameter workpieces between the wheels with each workpiece center positioned a distance above ahorizontal plane through the grinding wheel center equal to approximately one-third the workpiece diameter and wherein the regulating wheel contacts each such workpiece at a point thereon approximately level with the workpiece center.

It is still a further object of the present invention to disclose and provide an improvement in centerless grinding machines as in the foregoing object wherein the constant blade angle provided is approximately 24 and 7, the blade angle being the angle defined between the workpiece support top surface and a horizontal plane through the grinding wheel center, and the regulating wheel feed angle, defined by the included angle between the plane of regulating wheel movement and a horizontal plane v through the grinding wheel center, is approximately tution of constant angle work support blades of different thicknesses which are compatible with the size of workpiece being ground.

SUMMARY OF THE INVENTION Generally stated, the improvement in centerless grinding machine according to the present invention comprises the provision of a regulating wheel support assembly for mounting a regulating wheel for movement both horizontally and inclined to a grinding wheel and associated work support provided on the machine bed for easily and adaptably grinding diierent diameter workpieces between the wheels.

More particularly, the improvement in centerless grinding machine having a machine bed mounting a grinding wheel, a regulating wheel and a work support for supporting work to be ground between the wheels, according to the present invention, comprises the provision of a regulating wheel support assembly including both a main base mounted for horizontal movement relative to the grinding wheel and a sub-base rotatably mounting the regulating wheel which is in turn mounted on the main base for relative movement therewith in a direction inclined to the horizontal in order to allow adjustment of the position of the regulating wheel relative to the grinding wheel in a plane inclined upwardly away from a point of zero clearance between the wheels.

More specifically, the plane in which the regulating wheel is adjustably movable by its `sub-base relative to the main base of theregulating wheel support assembly, according to the present invention, is provided so that the regulating wheel is adjustable to successively contact a plurality of different diameter workpieces to be ground between the wheels at contact points thereon level with the workpiece centers when such different diameter workpieces are successively ground on the machine with their centers spaced above a horizontal plane through the grinding wheel axis a distance equal to approximately one-third of their respective diameters, such plane in the preferred embodiment of the invention making an included angle of approximately 18 and40 with a horizontal plane through the grinding wheel center dened by its axis of rotation A constant blade angle is provided for the work supporfgin the preferred practice of the invention of approximately 24 and 7', such angle being defined by the included angle between the work rest top surface and a horizontal plane through the grinding wheel center defined by its axis of rotation.

A more complete understanding of the improvement in centerless grinding machines will be aiforded to those skilled in the art from a consideration of the following detailed explanation of a preferred exemplary embodiment of centerless grinding machine according to the present invention. Reference will be made to the appended sheets of drawings wherein:

FIG. 1 is a plan view of the preferred exemplary embodiment of improvement in a centerless grinding machine accordingl to the present invention;

FIG. 2 is a side elevation view of the improvement in centerless grinding machine of FIG. 1;

FIG. 3 is a vertical section view of the machine of FIG. 1 taken therein along the vertical plane III-III;

FIG. 4 is a detail transverse section view of a portion of the machine of FIG. 3 taken therein a'long the plane IV-1V;

FIG. 5 is a transverse sectional View of a portion of the machine of FIG. 3 taken therein along the plane V-V;

FIG. 6 is a vertical section through the portion of the present machine shown in FIG. 5 taken therein along the plane VI-VI;

FIG. 7 is a detail view of the portion of the machine of FIG. 6 taken therein along the plane VII-VII;

FIG. 8 is a schematic representation of the machine of FIGS. 1 through 7 illustrating the relative positioning of the grinding wheel, regulating wheel and work support to position each workpiece with its center line a distance above the grinding wheel center line equal to approximately one-third of the workpiece diameter;

FIGS. 9 and 10 are detailed sectional views of the work support assembly portion of the machine of FIGS. 1 through 8 taken in FIG. 8 in the planes IX--IX and X-X respectively;

FIG. 11 is a diagram illustrating a plurality of different diameter circles generated in ever enlarging diameters from a point adjacent the grinding wheel circumference level with the grinding wheel center line and illustrating the generation of both the feed angle for the regulating wheel and the work supporting blade angle relative to the grinding wheel and workpieces to be ground on the machine;

FIG. 12 is a side elevation of an exemplary embodiment of truing or dressing apparatus for truing the grinding wheel and regulating wheel of the exemplary embodiment of machine of FIGS. 1 through 11; and

FIG. 13 is a side elevation of the exemplary embodiment of grinding'machine of FIGS. 1 through 11 showing the regulating wheel positioned at a point of zero clearance with the grinding wheel.

A detailed explanation of a preferred exemplary embodiment of the improvement in centerless grinding machine, will now be made. Referring iirst to FIGS. 1 through 4, the preferred exemplary embodiment includes a machine bed 10 mounted on a suitable frame or bed supporting structure 11 with a grinding wheel 12, a regulating wheel 13 and a work support 14 positioned on bed 10 to hold a workpiece 15 between the Wheels 12 and 13.`

As best seen in FIG. 4, a conventional grinding wheel 12 is rotatably mounted in a xed position on the machine bed 10 by securing grinding wheel 12 on a reduced diameter or shaft portion 16 of a spindle 17 rotatably mounted within a journal housing 18 by conventional roller bearings 19 and 20. A pulley 21 is secured by screw 22 to the rearward end 23 of spindle 17 within housing 18 and is driven by a drive belt 24 which -passes through an appropriate slot or opening 2S in bed 10 to and about a second pulley 26 (FIGS. 2 and 3) which is adapted to be driven by a motor means 27 Via a second drive belt 28. Motor means 27 may comprise an electric motor mounted on a flange support 27a secured Iwithin the machine bed supporting structure 11 as illustrated in FIG. 3. In the preferred exemplary embodiment the grinding wheel need never be moved for adjusting the machine for receiving diierent sized diameter workpieces as hereinafter explained.

In the preferred exemplary embodiment of centerless grinding machine, the work support 14 includes a work rest or fixture 30 mounting the workrest blade 31 on a slide block 32 slidably mounted by conventional dovetailed ways in an upstanding portion 33 of the machine bed 10. Blade 31 is received in a blade slot 34 provided in xture 30, as seen in FIG. 3, and is retained therein by pivotable side plates, as plate 35, as seen in FIG. 2. Fixture 30 is removably retained on slide 32 by the movable spring arms on either` side, as arm 36 as seen in FIG. 2. Slide 32 is movable horizontally along the top of the machine bed portion 33 by manually rotating knurled knob 37, against standard 38, causing horizontal movement of rod 39 which has slide block 32 secured thereto at one end and is threadably received at its opposite end within the internally threaded knob 37. The work rest blade 31 may thereby be very easily and accurately adjusted longitudinally on the machine bed portion 33 to place the blade top surface upon which the workpiece 15 rests in selectable positions of adjustment relative to the grinding wheel 12.

As particularly contemplated within the present invention, a regulating wheel support assembly is provided to mount regulating wheel 13 for movement relative to the -fixed axis of grinding wheel 12 in a plane inclined to and extending upwardly away from the point of zero contact between the regulating wheel and grinding wheel, illustrated in FIG. 13. The preferred exemplary embodiment of such regulating wheel support assembly is indicated generally at 40 and includes a main base 41 mounted for adjustable horizontal movement along the bed portion 33 and a sub-base portion 42 mounted on base 41 for adjustable movement in a plane inclined to grinding wheel 12 in a manner hereinafter explained.

As best seen in FIGS. 3 and 5, the main base 41 is mounted for horizontal movement relative to the machine bed 10, particularly upstanding portion 33, by conventional ways 43 and 44 formed in longitudinally extending block 45. Bearing blocks or inserts 46 and 47 are provided on the depending leg portions of base 41 to engage and slide upon the bed associated ways 43 and 44, respectively, as best seen in FIG. 5. Referring to FIG. 3, the horizontal adjustment of main base 41 relative to the fixed axis grinding wheel 12 may be accomplished by manual rotation of the knurled adjustment knob 48 rotatably mounted in standard 38 and receiving the threaded end of rod 49 secured to the main base 41.

Regulating wheel 13 is rotatably mounted upon the sub-base 42 mounted for movement on main base 41 in a plane inclined to the horizontal and is rotated by a power connection with the motor means 27 as best seen in FIGS. 1, 3, and 6. In the preferred exemplary embodiment, such sub-base 42 includes a yoke member 50 including a web portion 51 with spaced side arms 52 and 53 in which the regulating wheel shaft 54 is rotatably journaled. Regulating -wheel 13 is fixed upon the shaft 54 which is adapted to be rotated by a exible drive means to allow a universal movement of the wheel 13 and its mounting means.

The flexible drive means, indicated generally at 55, and best seen in FIG. 6, includes a exible drive cable 56 driven by a speed reduction or transmission means 57 operably connected to and driven by motor 27. Drive cable 56 is secured at its upper end to a pinion gear 58 adapted to drive a worm gear provided at 59 on the regulating wheel shaft 54 within a drive housing 60 connected to the leg 52 of sub-base yoke member 50. Gear 58 is rotatably journaled in the bearing means 61 secured in the vertically drilled or apertured mid-portion 62 of drive housing 60. A shield portion 63 is provided on the lower end of housing 60 to overlie the longitudinally slidable drive cable guide 64 mounted to the machine base 10. As seen in FIGS. 5 and 6, cable guide 64 may be formed of a suitable plastics material having a low coeflicient of friction with laterally extending side anges to overlie and underlie marginal portions of base adjacent a longitudinal slot or opening 65 provided in base 10. Guide 64 further includes an upstanding tubular portion 66 which normally extends upwardly within shield 63, as seen in FIGS. 5 and 6, the drive cable 56 being sufliciently long and exible to allow both Vertical and lateral movement of the regulating wheel 13 and its associated drive means including the pinion 58 within housing 60.

Means are provided for mounting sub-base 42 for movement relative to main base 41 in a plane inclined to the machine bed and the point of zero contact between wheels 12 and 13 illustrated in FIG. 13. Referring particularly to FIGS. 1 through 3, such means for mounting sub-base 42 on base 41 includes a regulating wheel arbor 70 slidably received within a conventional arbor sleeve 71 fitted within a tubular head portion 72 formed integrally of main base 41 and retained therein by the end nut 73. At its lower angularly oifset end 74, which is of reduced diameter, arbor mounts a calibrated collar which mounts sub-base 42 for rotation relative thereto about a horizontal axis. As seen in FIG. 3, web portion 51 of sub-base 50 is provided with a circular prominence 76 which is snugly received within collar 75. As seen in FIG. 7, locating pins or screws 77 and 78 may be provided, extending through chamfered arcuate slots 79 and 80 in collar 75 into the `web portion 51 of subbase yoke 50 in order to secure the sub-base 42 in any desired angular position relative to collar 75 and arbor 70 within the extent permitted by the slots 79 and 80.

The upper end of regulating wheel arbor 70 is internally threaded, as indicated at 81, FIG. 3, to receive mating threads 82 formed on the lower end of a hand crank shaft 83 adapted to be rotated by hand crank 84. Shaft 83 and hand crank 84 are mounted by a journal nut or member 85 welded or otherwise fastened to an externally threaded sleeve 86 which is threaded into an internally threaded sleeve 87 seated by a bottom flange 88 on an upper ange 89 of arbor Sleeve 71. A bushing 90 is provided to facilitate sliding movement of arbor 70 past the seated juncture of sleeves 87 and 7.1 as seen in FIG. 3. It will -be apparent to those skilled in the art from the foregoing explanation of the means for mounting the subbase 42, that manual rotation of hand crank 84 will cause move-ment of the regulating wheel 13, cantilevered outwardly from main base 41 by arbor 70, in a plane inclined to the horizontal plane of the machine bed and particularly, inclined to the grinding wheel 12. The angle of inclination of the plane within which the regulating wheel 13 is adjustably movable by manipulation of hand crank 84 is a critical aspect of the full enjoyment of the advantages and objects sought to be achieved by the present invention. The manner of determining the inclination of such inclined plane within which regulating lwheel 13 is adjustable as well as the exact preferred angle of inclination arrived at thereby will now be explained in detail.

In order to reduce the amount of setup time and readjusting of the relative positioning of the grinding wheel 12, regulating wheel 13 and work support 14, in addition to the provision of means for mounting regulating wheel 13 for movement in a direction both horizontal and inclined to the grinding wheel, a preferred critical angle of inclination for such regulating wheel adjustment exists for a preferred handling of a plurality of dilferent diameter workpieces successively without the need for relocating the grinding wheel 12 or work support 14.

Referring for the moment to FIG. 8, a partially schematic representation of grinding wheel 12, regulating wheel 13 and work support 14 is presented illustrating the preferred mounting of a tubular workpiece 15 having a generally circular cross-section. I have found that in the preferred operation of the described centerless grinding machine, each workpiece 15 should be maintained -by the work support -14 and regulating wheel 13 in a position wherein the center or C G. of the workpiece is positioned a distance above a horizontal axis of rotation of the grinding wheel equal to about one-third its diameter. Further, the point of contact between regulating wheel 13 and the workpiece 15 is preferably at a point on the workpiece circumference level with the workpiece center or C.G. With these two criteria in mind, a plurality of ideally located hypothetical true round workpieces represented by the plurality of circles 90, 91 and 92 are shown in FIG. 11. The outer circumference of grinding wheel 12 is represented by the curve 12' in FIG. 1l with a horizontal plane passing through the grinding wheel center line being represented by line 96. Each of the generated circles 90, 91 and 92 has its center of rotation 93, 94 and 95, respectively, positioned a distance (1/3 d.) equal to one-third of its diameter above the plane represented by line 96 passing through the grinding wheel axis of rotation or center, the letters d', d and d" representing the diameters of circles 90, 91 and 92 respectively.

Having thus generated the ideal location for the placement of a plurality of workpieces of generally circular diameter by the circles 90, 91 and 92 in FIG. 11, the preferred blade angle, the angle of the top surface of work support 14 relative to the plane indicated by line 96 through the center of grinding Wheel 12, has been deter'- mined by drawing a line 97 tangent to the lower portions of each of circles 90, 91 and 92. The included angle b between the plane for the work support surface indicated by line 97 and the plane indicated by line 96, is thus the preferred blade angle for the work support blade 31. By the above procedure, I have found that the ideal blade angle for operation of the described machine is approximately 2`47.

Still referring to FIG. ll, the angle of the plane in which the regulating wheel is ideally movable is computed by drawing a line 98 through a point of zero clearance between the wheels, indicated at 99, and the successive ideal contact points 100, 101 and 102 where regulating wheel 13 is to contact the ideally located workpieces represented by circles 90, 91 and 92. Regulating wheel-workpiece contact point 100, 101 and 102 are chosen at the locations where the regulating Wheel will contact each workpiece at the workpiece periphery on an approximate level with the workpiece center line and on a side thereof away from the grinding wheel 12. Through the above analysis, I have determined that the ideal included angle a between the plane within which the regulating wheel is movable, represented by line 98, and the horizontal plane through the grinding wheel center line, represented by line 96, is approximately 1840'.

In view of my foregoing determinations with regard to the ideal location of workpieces of dilerent diameters in the specific arrangement of grinding wheel, regulating wheel and work support 14 the preferred exemplary ernbodiment is to be constructed with the regulating wheel support assembly sub-base 42 (FIG. 3) mounted for movement in a plane having an included angle of 1840 with the horizontal plane passing through the grinding wheel center line. Further, while work support or work rest blades 31 of different thicknesses are preferably employed for workpieces of different diameters, it is contemplated that each such workpiece support blade 31 shall have an upper surface having a blade angle b equal to 247. I have found that when the centerless grinding machine as herein disclosed is constructed with the blade angle and regulating wheel adjustment feed angle (angles b and a in FIG. ll respectively), that a plurality of different diameter workpieces may be successively ground on the described grinding machine by merely manually adjusting the position of regulating wheel 13 by hand crank 84 and replacing the constant blade angle work support blades 31 of different thicknesses as required for the different diameter workpieces. It should be apparent to those skilled in this art thatthe ease' of setup for the grinding of such different diameter workpieces is exceptionally advantageous over the ease of setting of prior grinding machines.

The improvement in centerless grinding machine, according tothe present invention, is particularly adapted for ease of truing or dressing of the grinding and regulating Wheels as Well as resetting of the machine for further grinding operations. Referring `to FIG. 12, a wheel dressing tool 110 is illustrated mounted on a mounting block 111 positioned and retained on slide 32 by the side arms thereon, as arm 36. The mounting of the dressing tool 110 on slide 32 allows truing of wheels 12 and 13 relative to each other and the machine bed upon which each is mounted. After such dressing operations, the described machine is very easily set up for the beginning of grinding operations. The dressing tool 110 and its 4mounting block 111 are merely removed and the regulating wheel support assembly is moved horizontally on ways 41 until regulating wheel 13 reaches the zero clearance point with grinding wheel 12, as seen in FIG.

13, with the centersof both wheels equidistant` above the machine bed. Having thus set wheels 12 and 13 in alignment to each other for subsequent grinding operations, wheel 13 is backed upwardly away from grinding wheel 12 in its inclined plane of movement provided by the mounting of sub-base 42 on assembly base 41. Hand crank 84 is merely rotated to back the sub-base 42 up and away from the grinding wheel to allow replacement of the work support 14, as seen inFIGS. 1 through 3, rendering the machine immediately available for use in grinding a plurality of different diameter workpieces in any successive diameters required by the job shop operators production requirements.

As will be apparent to those skilled in the art from a consideration of the foregoing detailed explanation, both through-feed and in-feed methods of grinding may be easily accomplished on the machine of the present invention. The fast-screw co-axial thread built within the hand crank mechanism, as illustrated in FIG. 3, has the distinct advantage of allowing rapid adjustment of the regulating wheel position for the handling of parts with multiple diameters which are to be plunge ground by the in-feed method. In grinding workpieces according to the through-feed method, the sub-base 42 may be rotated or tilted about the offset end 74 upon which it is mounted (FIG. 3) to provide the required l to 3 degrees of tilt necessary for imparting transverse movement to work parts ground between the wheels. The regulating wheel is alwaysidressed on the desired degree of tilt or inclination to the horizontal axis about which it is rotatable for through-feed operations.

It should be understood by those skilled in the art that the foregoing detailed explanation of a centerless grinder is intended to be illustrative of a preferred exemplary embodiment only and that other embodiments, modiiications and adaptations of the improvements in centerless grinders may be made Within the scope of the present invention which is defined and limited only by the following claims.

I claim:

1. A centerless grinding machine `capable of being set up in a few minutes comprising, in combination, a machine bed; a power-operated work-grinding wheel mounted on the machine bed to rotate about a xed horizontal axis; a main base adjustably supported on the machine bed; manually operable means for adjusting the main base horizontally toward and from the work-grinding wheel; a sub-base adjustably supported on the main base and movable thereon in a plane which is inclined to the horizontal and is above the axis of rotation of the work-grinding wheel; a power-operated regulating wheel which is supported on the sub-base for rotation about a generally horizontal axis; manually operable means for moving the sub-base and hence said regulating wheel toward and from the work-grinding wheel; the direction of movement of the sub-base being at an angle of approximately 1840 relative to a horizontal plane through the axis of rotation of the work-grinding wheel; a work rest blade iixedly supported in a generally vertical position and having a top surface below the aforesaid horizontal plane and between the work-grinding wheel and the regulating wheel, so that a workpiece may rest on the top surface of the work rest blade during the grinding operation; the angle between the top surface of the work rest blade and the aforesaid horizontal plane being aproximately 247'.

2. A centerless grinding machine capable of being set up in a few minutes comprising, in combination, a machine bed; a power-operated work-grinding wheel mounted on the machine bed to rotate about a fixed horizontal axis; a power-operated regulating wheel which is adjustably mounted upon the machine bed and which rotates about a generally horizontal axis; manually operable :means for moving the regulating Wheel toward and from the work-grinding wheel; the direction of movement of the regulating wheel being at an angle of approximately 1840 relative to and above the horizontal plane through the axis of rotation of the work-grinding Wheel; a work rest blade xedly supported in a generally Vertical position having a top surface below the aforesaid horizontal plane and between the work-grinding wheel and the regulating wheel, so that a workpiece may rest on the top surface of the work rest blade during the grinding operation; the angle between the top surface of the work rest blade and the aforesaid horizontal plane being approximately 247'.

3. A centerless grinding machine capable of being set up in a few minutes comprising, in combination, a machine bed; a power-'operated work-grinding wheel mounted on the machine bed to rotate about a xed horizontal axis; a power-operated regulating wheel which is adjustably mounted on the machine bed and which rotates about a generally horizontal axis; a work rest blade xedly supported in a generally vertical position and having an upper surface below the horizontal axis of rotation of the work-grinding wheel and between the work-grinding wheel and the regulating wheel, so that one of a series of workpieces may be supported on the upper surface of the work rest blade; the contact points between the regulating wheel, as it is adjusted, and the peripheries of the several workpieces so supported, being on an approximate level with the centerlines of the Workpieces; the included angle between the direction of movement of the regulating wheel and the horizontal plane through the axis of rotation of the work-grinding wheel being approximately 1840; the included angle between the upper surface of the work rest blade and the horizontal plane through the axis of the work-grinding wheel being approximately 247'.

References Cited UNITED STATES PATENTS 1,709,671 4/ 1929 Kearns 51-105 1,938,756 12/1933 Booth 51-103 2,012,078 8/1935 Binns 51-103 2,048,467 7/ 1936 Roehm 51--103 2,761,253 9/ 1956 Barhorst 51-103 LESTER M. SWINGLE, Primary Examiner 

